Effect of salty fog on flashover characteristics of OCS composite insulators

摘要

To study the flashover characteristics of the fog water in saline-alkali areas for high-speed railway OSC insulators, the spatial distributions of both the potential and electric field of soiled insulators in the presence of salty fog are analyzed using COMSOL Multiphysics, a multi-physics coupling software. Furthermore, to analyze the effect of the contamination of insulators due to salty fog water , a saline solution is used for staining an insulator sample by using the solid coating method. In an artificial climate chamber, the salty fog environment is simulated, and the flashover voltage for different salty fog water conductivities and surface staining are obtained. The salt-density correction coefficient K is also proposed. It provides a strong basis for the selection of railway insulators in saline-alkali areas. The results show that the salty fog water changes the original surface equivalent salt density, ρESDD, by wetting the existing fouling layer on the surface of the insulator, so that the original surface contamination layer becomes equivalent to Kρ_ESDD; the smaller is the value of ρESDD of the insulator surface, the larger is the value of K; the surface of the same insulator is dirty, and as the concentration of salty fog-water increases, K also increases.